1. Field of the Invention
The present invention relates to a developer regulating member for regulating a developer and to a developing apparatus including the same. More particularly, it relates to a developer regulating member and to a developing apparatus suitable for use in an electrophotographic type image forming apparatus, for example, a copying machine, a printer or a facsimile machine.
2. Description of the Related Art
Hitherto, in such a type of image forming apparatus, an electrostatic latent image formed on an image bearing member has been visualized as a toner image by a developing apparatus.
As such a developing apparatus, for example, a dry one-component contact developing apparatus has been proposed and put to practical use. In this case, mostly, an electrostatic latent image is developed by pressing or contacting a rotating electrostatic latent image bearing member with a similarly rotating toner carrying member (developer carrying member) at a suitable relative peripheral velocity difference. In addition, the apparatus has many advantages. For example, no magnetic material is required so that the apparatus can be easily simplified and miniaturized. Furthermore, use of non-magnetic toner makes it possible to apply the apparatus to a full color image forming apparatus.
As the toner carrying member, a developing roller having elasticity and conductivity can be used. That is, since development is conducted by pressing or contacting it with the electrostatic latent image bearing member, the developing roller is made of an elastic material in order to prevent the electrostatic latent image bearing member from being damaged especially when it is a rigid member.
Also, the developing roller may be used by providing a conductive layer on a surface thereof or in the vicinity of the surface and applying a developing bias.
Further, for the purpose of imparting charges to the toner and forming a uniform thin layer of toner, a developing blade as a development regulating member may be abutted to the toner carrying member. In this case, it is possible to use an elastic blade made of rubber or a metallic thin plate having spring elasticity as the developing blade.
FIG. 8 shows a conventional developing apparatus.
A developing roller 81, which is a toner carrying member, is an elastic roller having conductivity, which has a base layer of silicone rubber having coated thereon acrylic urethane based rubber as a surface layer, It is rotatively driven in the direction as indicated by an arrow A.
A developing blade 82 is supported by a blade supporting sheet metal 83, and the vicinity of the leading end on the free end side of the developing blade contacts face to face with the peripheral surface of the developing roller 81.
Further, an elastic roller 84 is abutted to the developing roller 81 and is rotatively driven in the direction indicated by an arrow B. The elastic roller 84 is a sponge roller and is intended to supply toner to the developing roller 81 and scrape away the toner remaining on the developing roller undeveloped. The elastic roller 84 is arranged on the upstream side of the developing blade 82 in the rotational direction of the developing roller 81.
Toner 85 is a non-magnetic one-component developer. For the purpose of improving charging property and transfer property of toner, a suitable amount of hydrophobic silica is externally added.
In the developing apparatus of the above-mentioned structure, a satisfactory thin layer of the non-magnetic toner 85 can be formed on the developing roller 81 and an electrostatic latent image on the bearing member can be satisfactorily developed.
However, in the conventional technology as described above, it is desired to use toner having a smaller particle size or having an ensphered configuration for further improvement of high quality image. Repeating development operation by using such toner caused a problem in that an image failure of number of fine streaks is generated when a thin plate of metal such as SUS or phosphor bronze is used as a developing blade.
The present invention has been made in view of the above, and an object of the present invention is to provide a developer regulating member and a developing apparatus for forming a uniform layer of developer on a developer carrying member.
Another object of the present invention is to provide a developer regulating member and a developing apparatus in which the occurrence of a streak-like image failure in images is prevented.
Another object of the present invention is to provide a developer regulating member and a developing apparatus which can form satisfactory images even when toner having a reduced particle size or toner having an ensphered configuration is used.
Further objects and features of the present invention will become more apparent upon reading the following detailed description of the present invention with reference to the attached drawings.